I'm thinking like this...
Brightness Fall <= to the release of the album, we knew it will be in Sept
Explode forward at once <= must be more than 1 to explode at once, so we are expecting a double album. Or simply just the album and LPU10
Beautifully Strong <== Could be pointed to the lyrics, the lyric is beautiful but strong =.="
Ground Breaking <== what can break the ground? Great force and heavy thing, could point to how the album sound
Time <=== could mean "ever yet", like it won't be like anything they did in the past.